US7816426B2 - Superabsorbent polymer compositions having color stability - Google Patents

Superabsorbent polymer compositions having color stability Download PDF

Info

Publication number
US7816426B2
US7816426B2 US11/778,372 US77837207A US7816426B2 US 7816426 B2 US7816426 B2 US 7816426B2 US 77837207 A US77837207 A US 77837207A US 7816426 B2 US7816426 B2 US 7816426B2
Authority
US
United States
Prior art keywords
superabsorbent polymer
polymer composition
weight
acid
superabsorbent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related, expires
Application number
US11/778,372
Other languages
English (en)
Other versions
US20090023848A1 (en
Inventor
Iqbal Ahmed
Mirko Walden
Brian King
Scott J. Smith
Harald Schmidt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Evonik Corp
Original Assignee
Evonik Stockhausen LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US11/778,372 priority Critical patent/US7816426B2/en
Application filed by Evonik Stockhausen LLC filed Critical Evonik Stockhausen LLC
Assigned to STOCKHAUSEN, INC. reassignment STOCKHAUSEN, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SCHMIDT, HARALD, SMITH, SCOTT J., WALDEN, MIRKO, AHMED, IQBAL, KING, BRIAN
Priority to KR1020107001034A priority patent/KR101474229B1/ko
Priority to PCT/US2007/089047 priority patent/WO2009011717A1/en
Priority to CN2007800537912A priority patent/CN101802029B/zh
Priority to JP2010516971A priority patent/JP5164229B2/ja
Priority to EP07866086.7A priority patent/EP2167552B1/en
Priority to TW097122668A priority patent/TWI406875B/zh
Publication of US20090023848A1 publication Critical patent/US20090023848A1/en
Assigned to EVONIK STOCKHAUSEN, INC. reassignment EVONIK STOCKHAUSEN, INC. CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: STOCKHAUSEN, INC.
Assigned to EVONIK STOCKHAUSEN, LLC reassignment EVONIK STOCKHAUSEN, LLC CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: EVONIK STOCKHAUSEN, INC.
Priority to US12/884,713 priority patent/US8063118B2/en
Publication of US7816426B2 publication Critical patent/US7816426B2/en
Application granted granted Critical
Priority to US13/296,861 priority patent/US8236876B2/en
Assigned to EVONIK DEGUSSA CORPORATION reassignment EVONIK DEGUSSA CORPORATION MERGER (SEE DOCUMENT FOR DETAILS). Assignors: EVONIK STOCKHAUSEN, LLC
Assigned to EVONIK CORPORATION reassignment EVONIK CORPORATION CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: EVONIK DEGUSSA CORPORATION
Expired - Fee Related legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/04—Acids; Metal salts or ammonium salts thereof
    • C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/42—Use of materials characterised by their function or physical properties
    • A61L15/56—Wetness-indicators or colourants
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/42—Use of materials characterised by their function or physical properties
    • A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F222/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical and containing at least one other carboxyl radical in the molecule; Salts, anhydrides, esters, amides, imides, or nitriles thereof
    • C08F222/10—Esters
    • C08F222/1006—Esters of polyhydric alcohols or polyhydric phenols
    • C08F222/103—Esters of polyhydric alcohols or polyhydric phenols of trialcohols, e.g. trimethylolpropane tri(meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/30—Sulfur-, selenium- or tellurium-containing compounds

Definitions

  • a superabsorbent material in general refers to a water-swellable, water-insoluble, material capable of absorbing at least about 10 times its weight, and up to about 30 times or more its weight in an aqueous solution containing 0.9 weight percent sodium chloride solution in water.
  • the present invention relates to superabsorbent polymer compositions which absorb water, aqueous liquids, and blood.
  • a superabsorbent polymer is a crosslinked partially neutralized polymer that is capable of absorbing large amounts of aqueous liquids and body fluids, such as urine or blood, with swelling and the formation of hydrogels, and of retaining them under a certain pressure in accordance with the general definition of superabsorbent material.
  • Superabsorbent polymer compositions may include post-treatment of the superabsorbent polymer such as surface crosslinking, surface treatment, and other treatment.
  • Superabsorbent polymer particles are particles of superabsorbent polymers or superabsorbent polymer compositions.
  • SAP may be used in place of superabsorbent polymer, superabsorbent polymer composition, and particles herein.
  • superabsorbent polymer compositions include crosslinked polyacrylic acids or crosslinked starch-acrylic acid graft polymers, in which some of the carboxyl groups are neutralized with sodium hydroxide solution or potassium hydroxide solution.
  • a primary use of superabsorbent polymer compositions is in sanitary articles, such as babies' diapers, incontinence products, or sanitary towels. For fit, comfort, and aesthetic reasons, and from environmental aspects, there is an increasing trend to make sanitary articles smaller and thinner. This is being accomplished by reducing the content of the high volume fluff fiber in these articles. To ensure a constant total retention capacity of body fluids in the sanitary articles, more superabsorbent polymer composition content is being used in these sanitary articles.
  • the present invention relates to superabsorbent polymer composition having long-term color stability, and to methods of preparing the color-stable superabsorbent polymer composition, in particular retaining a measurable whiteness.
  • An embodiment of the present invention comprises at least a superabsorbent polymer composition comprising a superabsorbent polymer comprising a) from about 55% to about 99.9% by weight of the superabsorbent polymer of polymerizable unsaturated acid group containing monomer based on the superabsorbent polymer; and b) from about 0.001% to about 5% by weight of internal crosslinking agent based on the polymerizable unsaturated acid group containing monomer; c) from about 50 to 1000 ppm of a thermal initiator based on the polymerizable unsaturated acid group containing monomer; wherein the superabsorbent polymer has a degree of neutralization of greater than about 25%; wherein elements a), b), and c) are polymerized into a crosslinked hydrogel, which is then prepared into superabsorbent polymer particles; the superabsorbent polymer composition further comprising the following additives to form superabsorbent polymer composition particles, i) from about 0.001% to
  • the present invention includes many and various embodiments that include, but are not limited to the following embodiments:
  • the present invention is directed to absorbent compositions or sanitary articles that may contain superabsorbent polymer compositions of the present invention.
  • FIG. 1 is a side view of the test apparatus employed for the Free Swell Gel Bed Permeability Test
  • FIG. 2 is a cross-sectional side view of a cylinder/cup assembly employed in the Free Swell Gel Bed Permeability Test apparatus shown in FIG. 1 ;
  • FIG. 3 is a top view of a plunger employed in the Free Swell Gel Bed Permeability Test apparatus shown in FIG. 1 ;
  • absorbent article generally refers to devices that can absorb and contain fluids.
  • personal care absorbent articles refer to devices that are placed against or near the skin to absorb and contain the various fluids discharged from the body.
  • the term “Darcy” is a CGS unit of permeability.
  • One Darcy is the permeability of a solid through which one cubic centimeter of fluid, having a viscosity of one centipoise, will flow in one second through a section one centimeter thick and one square centimeter in cross-section, if the pressure difference between the two sides of the solid is one atmosphere. It turns out that permeability has the same units as area; since there is no SI unit of permeability, square meters are used.
  • One Darcy is equal to about 0.98692 ⁇ 10 ⁇ 12 m 2 or about 0.98692 ⁇ 10 ⁇ 8 cm 2 .
  • disposable is used herein to describe absorbent articles that are not intended to be laundered or otherwise restored or reused as an absorbent article after a single use.
  • Examples of such disposable absorbent articles include, but are not limited to, personal care absorbent articles, health/medical absorbent articles, and household/industrial absorbent articles.
  • crosslinked used in reference to the superabsorbent polymer refers to any means for effectively rendering normally water-soluble materials substantially water-insoluble but swellable.
  • a crosslinking means can include, for example, physical entanglement, crystalline domains, covalent bonds, ionic complexes and associations, hydrophilic associations such as hydrogen bonding, hydrophobic associations, or Van der Waals forces.
  • dry superabsorbent polymer composition generally refers to the superabsorbent polymer composition having less than about 10% moisture.
  • the units can comprise flakes, fibers, agglomerates, granules, powders, spheres, pulverized materials, or the like, as well as combinations thereof.
  • the particles can have any desired shape: for example, cubic, rod-like, polyhedral, spherical or semi-spherical, rounded or semi-rounded, angular, irregular, et cetera. Shapes having a high aspect ratio, like needles, flakes, and fibers, are also contemplated for inclusion herein.
  • particle or “particulate” may also include an agglomeration comprising more than one individual particle, particulate, or the like. Additionally, a particle, particulate, or any desired agglomeration thereof may be composed of more than one type of material.
  • polymer includes, but is not limited to, homopolymers, copolymers, for example, block, graft, random, and alternating copolymers, terpolymers, etc., and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term “polymer” shall include all possible configurational isomers of the material. These configurations include, but are not limited to isotactic, syndiotactic, and atactic symmetries.
  • polyolefin as used herein generally includes, but is not limited to, materials such as polyethylene, polypropylene, polyisobutylene, polystyrene, ethylene vinyl acetate copolymer, and the like, the homopolymers, copolymers, terpolymers, etc., thereof, and blends and modifications thereof.
  • polyolefin shall include all possible structures thereof, which include, but are not limited to, isotatic, syndiotactic, and random symmetries. Copolymers include atactic and block copolymers.
  • superabsorbent materials refers to water-swellable, water-insoluble organic or inorganic materials including superabsorbent polymers and superabsorbent polymer compositions capable, under the most favorable conditions, of absorbing at least about 10 times their weight, or at least about 15 times their weight, or at least about 25 times their weight in an aqueous solution containing 0.9 weight percent sodium chloride.
  • superabsorbent polymer composition refers to a superabsorbent polymer comprising a surface additive in accordance with the present invention.
  • superabsorbent polymer and “superabsorbent polymer preproduct” refer to a material that is produced by conducting all of the steps for making a superabsorbent polymer as described herein, up to and including drying the material, and coarse grinding in a crusher.
  • surface crosslinking means that the level of functional crosslinks in the vicinity of the surface of the superabsorbent polymer particle generally is higher than the level of functional crosslinks in the interior of the superabsorbent polymer particle.
  • surface describes the outer-facing boundaries of the particle. For porous superabsorbent polymer particles, exposed internal surface also are included in the definition of surface.
  • thermoplastic describes a material that softens when exposed to heat and which substantially returns to a non-softened condition when cooled to room temperature.
  • the term “whiteness index” when used herein is to be interpreted as based on measurement of uniform color spaces on the CIE 1976 L*a*b* scale for any illuminant as recommended by the Commission Internationale de l'Eclairage (CIE).
  • CIE L*a*b* scale is a simplified cube root version of the Adams-Nickerson space produced by the quantities of CIE L*a*b* in rectangular coordinates.
  • the relationship of the CIE L*a*b* scale and the CIE XYZ scale for any illuminant is described in the ASTM E 308 Standard Practice for Computing the Colors of Objects by Using the CIE System.
  • % by weight or “% wt” when used herein and referring to components of the superabsorbent polymer composition, is to be interpreted as based on the weight of the dry superabsorbent polymer composition, unless otherwise specified herein.
  • An embodiment of the present invention includes a superabsorbent polymer composition
  • a superabsorbent polymer composition comprising superabsorbent polymer particles surface treated with from about 0.01% to about 5% by weight of an antioxidant compound, based on the superabsorbent polymer composition wherein the antioxidant may be added to the polymerized product whether in crosslinked hydrogel or subsequent superabsorbent polymer particles or superabsorbent polymer composition form.
  • the superabsorbent polymer has a degree of neutralization of greater than about 25%; wherein elements a), b) and c) are polymerized into a crosslinked hydrogel, which is then prepared into superabsorbent polymer particles; the superabsorbent polymer composition further comprising the following additives to form superabsorbent polymer composition particles
  • a superabsorbent polymer as set forth in embodiments of the present invention is obtained by the initial polymerization of from about 55% to about 99.9% by weight of the superabsorbent polymer of polymerizable unsaturated acid group containing monomer.
  • a suitable monomer includes any of those containing carboxyl groups, such as acrylic acid, methacrylic acid, or 2-acrylamido-2-methylpropanesulfonic acid, or mixtures thereof. It is desirable for at least about 50% by weight, and more desirable for at least about 75% by weight of the acid groups to be carboxyl groups.
  • the acid groups are neutralized to the extent of at least about 25 mol %, that is, the acid groups are desirably present as sodium, potassium, or ammonium salts.
  • the degree of neutralization may be at least about 50 mol %.
  • the suitable monomer that can be copolymerized with the ethylenically unsaturated monomer may include, but is not limited to acrylamide, methacrylamide, hydroxyethyl acrylate, dimethylaminoalkyl (meth)-acrylate, ethoxylated (meth)-acrylates, dimethylaminopropylacrylamide, or acrylamidopropyltrimethylammonium chloride.
  • Such monomer may be present in a range of from 0% to about 40% by weight of the copolymerized monomer.
  • the superabsorbent polymer of the invention also includes internal crosslinking agents.
  • the internal crosslinking agent has at least two ethylenically unsaturated double bonds, or one ethylenically unsaturated double bond and one functional group that is reactive toward acid groups of the polymerizable unsaturated acid group containing monomer, or several functional groups that are reactive towards acid groups can be used as the internal crosslinking component and is desirably present during the polymerization of the polymerizable unsaturated acid group containing a monomer.
  • internal crosslinking agents include, but are not limited to, aliphatic unsaturated amides, such as methylenebisacryl- or -methacrylamide or ethylenebisacrylamide; aliphatic esters of polyols or alkoxylated polyols with ethylenically unsaturated acids, such as di(meth)acrylates or tri(meth)acrylates of butanediol or ethylene glycol, polyglycols or trimethylolpropane; di- and triacrylate esters of trimethylolpropane which may be oxyalkylated, desirably ethoxylated, with about 1 to about 30 moles of alkylene oxide; acrylate and methacrylate esters of glycerol and pentaerythritol and of glycerol and pentaerythritol oxyethylated with desirably about 1 to about 30 mol of ethylene oxide; allyl compounds, such as allyl
  • Ionic crosslinkers such as multivalent metal salts may also be employed. Mixtures of the crosslinking agents mentioned can also be employed.
  • the content of the internal crosslinking agents is from about 0.001% to about 5% by weight such as from about 0.2% to about 3% by weight based on the total amount of the polymerizable unsaturated acid group containing monomer.
  • the superabsorbent polymer composition of the invention may also include from about 50 to 1000 ppm of a thermal initiator based on the polymerizable unsaturated acid group containing monomer.
  • Thermal initiators may include persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; peroxides such as benzoyl peroxide, t-butyl peroxide, and methyl ethyl ketone peroxide; peroxyesters such as t-butylperoxypivalate, t-amylperoxypivalate, t-amylperoxy-2-ethylhexanoate and t-butylperoxyisobutyrate; and azo compounds such as azonitrile compounds, azoamidine compounds, cyclic azoamidine compounds, azoamide compounds, alkylazo compounds, 2,2′-azobis(2-amidinopropane) dihydrochloride, and 2,2′-azo
  • initiators can be used for initiation of the free-radical polymerization.
  • Suitable initiators include, but are not limited to, azo or peroxo compounds, redox systems or UV initiators, sensitizers, and/or radiation.
  • the superabsorbent polymer becomes a crosslinked hydrogel which is then prepared into superabsorbent polymer particles.
  • the superabsorbent polymer particles may then be surface crosslinked by the addition of a surface crosslinking agent and heat-treatment.
  • surface crosslinking is a process that is believed to increase the crosslink density of the polymer matrix in the vicinity of the superabsorbent particle surface with respect to the crosslinking density of the particle interior.
  • desirable surface crosslinking agents include chemicals with one or more functional groups that are reactive toward pendant groups of the polymer chains, typically the acid groups.
  • the surface crosslinking agent may be present in an amount of from about 0.001% to about 5% by weight of the dry superabsorbent polymer composition, and such as from about 0.1% to about 3% by weight, and such as from about 0.1% to about 1% by weight, based on the weight of the dry superabsorbent polymer composition. Applicants have found that a heat treatment step after addition of the surface crosslinking agent is desirable.
  • Surface crosslinking agents are chemical compounds that may contain functional groups capable of reacting with carboxylic acid or carboxyl groups.
  • Surface crosslinking agents may include two functional groups such as some alcohol, amine, aldehyde, and carbonate groups may be used.
  • Crosslinker molecules having multiple different functions may also be employed, such as polyols, polyamines, polyaminoalcohols, and alkylene carbonates.
  • Ethylene glycol diethylene glycol, triethylene glycol, polyethylene glycol, glycerol, polyglycerol, propylene glycol, diethanolamine, triethanolamine, polypropylene glycol, block copolymers of ethylene oxide and propylene oxide, sorbitan fatty acid esters, ethoxylated sorbitan fatty acid esters, trimethylolpropane, ethoxylated trimethylolpropane, pentaerythritol, ethoxylated pentaerythritol, polyvinyl alcohol, sorbitol, ethylene carbonate, propylene carbonate may be used. Polyols and ethylene carbonate may be used as surface crosslinking agents.
  • Surface crosslinking agents may be an alkylene carbonate followed by heating to effect surface crosslinking, which can improve the surface crosslinking density and the gel strength characteristics of the superabsorbent polymer particle. More specifically, the surface crosslinking agent is coated onto the superabsorbent polymer particulate by mixing the polymer particulate with an aqueous alcoholic solution of the alkylene carbonate surface crosslinking agent.
  • the amount of alcohol is determined by the solubility of the alkylene carbonate and is kept as low as possible for various reasons. Suitable alcohols are methanol, isopropanol, ethanol, butanol, or butyl glycol, as well as mixtures of these alcohols.
  • the solvent desirably is water, which typically is used in an amount of about 0.3% by weight to about 5.0% by weight, based on the weight of the dry superabsorbent polymer.
  • the alkylene carbonate surface crosslinking agent is dissolved in water without any alcohol.
  • the alkylene carbonate surface crosslinking agent may be applied from a powder mixture, for example, with an inorganic carrier material, such as silicone dioxide (SiO 2 ), or in a vapor state by sublimation of the alkylene carbonate.
  • the alkylene carbonate is distributed evenly on the particulate superabsorbent polymer.
  • mixing is effected in suitable mixers known in the art, such as fluidized bed mixers, paddle mixers, rotary drum mixers, or twin-worm mixers. It is also possible to carry out the coating of the particulate superabsorbent polymer during one of the process steps in the production of the particulate superabsorbent polymer.
  • a suitable process for this purpose is the inverse suspension polymerization process.
  • the heat treatment may be carried out as follows.
  • the heat treatment is at a temperature of from about 100° C. to about 300° C. Lower temperatures are possible if highly reactive epoxide crosslinking agents are used.
  • the thermal treatment is suitably at a temperature of from about 150° C. to about 250° C. In this particular aspect, the treatment temperature depends on the dwell time and the kind of alkylene carbonate. For example, at a temperature of about 150° C., the thermal treatment is carried out for one hour or longer.
  • a few minutes are sufficient to achieve the desired surface cross-linking properties.
  • the thermal treatment may be carried out in conventional dryers or ovens known in the art.
  • the superabsorbent polymer composition of the invention may further include from about 0.01% to about 5% by weight of an antioxidant based on the superabsorbent polymer composition that may be added to the polymerized product whether in crosslinked hydrogel or subsequent superabsorbent polymer particles or superabsorbent polymer composition particle form.
  • the antioxidant may be selected from a sulfite or bisulfite of an alkali metal, ammonium sulfite, sodium metabisulfite, ammonium bisulfite, sulfinic acid, 2-hydroxy-2-sulfinatoacetic acid, 2-hydroxy-2-sulfonatoacetic acid, 2-hydroxy-2-sulfonatoacetic acid, sulfamic acid, or sulfonic acid, and salts and derivatives of the foregoing.
  • 2-Hydroxy-2-sulfinatoacetic acid and 2-hydroxy-2-sulfonatoacetic acid in sodium salt forms (a pure form), in combination with sodium bisulfite are available commercially from Bruggemann Chemical, Heilbron, Germany, as BRUGGOLITE® FF6 and BRUGGOLITETM FF7 reducing agents.
  • 2-Hydroxy-2-sulfinatoacetic acid derivatives are disclosed in example 3 of U.S. Pat. No. 6,211,400, wherein example 3 of U.S. Pat. No. 6,211,400, is incorporated herein by reference.
  • the superabsorbent polymer composition of the invention may include up to about 1% by weight of the dry superabsorbent polymer composition of a chelating agent.
  • the chelating agent used in the present invention includes, for example, an aminocarboxylic acid metal chelating agent such as iminodiacetic acid, hydroxyethyl iminodiacetate, nitrilotriacetic acid, nitrilotripropionic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, pentasodium diethylenetriaminepentaacetate, triethylenetetraminehexaacetic acid, trans-1,2-diaminocyclohexanetetraacetic acid, N,N-bis(2-hydroxyethyl)glycine, diaminopropanoltetraacetic acid, ethylenediaminedipropionic acid, hydroxyethylenediaminetriacetic acid, glycoletherdiaminetetraacetic acid, dia
  • Chelating agents may be a pentasodium diethylenetriaminepentaacetate such as VersenexTM 80 chelating agent that is commercially available from The Dow Chemical Company.
  • VersenexTM 80 chelating agent is an aqueous solution of the pentasodium salt of diethylenetriaminepentaacetic acid.
  • the superabsorbent polymer composition of the present invention may include from 0 to about 5 wt % of a multivalent metal salt on the surface of the polymer, based on the weight of the dry superabsorbent polymer composition.
  • the multivalent metal salt is preferably water soluble.
  • preferred metal cations include the cations of Al, Fe, Zr, Mg and Zn.
  • the metal cation has a valence of at least +3, with Al being most preferred.
  • preferred anions in the multivalent metal salt include halides, chlorohydrates, sulfates, lactate, nitrates and acetates.
  • Examples of such multivalent metal salts include aluminium sulfate, and aluminum lactate.
  • a form of aluminum sulfate is hydrated aluminum sulfate, preferably aluminum sulfate having from 12 to 14 waters of hydration. Mixtures of multivalent metal salts may be employed.
  • the polymer and multivalent metal salt suitably are mixed by dry blending, or preferably in solution, using means well known to those skilled in the art. Aqueous solutions are preferred. With dry blending, a binder may be employed in an amount which is sufficient to ensure that a substantially uniform mixture of the salt and the superabsorbent polymer is maintained.
  • the binder may be water or a nonvolatile organic compound having a boiling point of at least 150° C. Examples of binders include water, polyols such as propylene glycol, glycerin and poly(ethylene glycol).
  • the superabsorbent polymer composition of the present invention may include up to about 5% by weight, and from about 0.001% to about 5% by weight, and from about 0.01% to about 0.5% by weight of the dry superabsorbent polymer composition of a polymeric coating, such as a thermoplastic coating, or a cationic coating, or a combination of a thermoplastic coating and a cationic coating.
  • a polymeric coating such as a thermoplastic coating, or a cationic coating, or a combination of a thermoplastic coating and a cationic coating.
  • the polymeric coating desirably is a polymer that may be in a solid, emulsion, suspension, colloidal, or solubilized state, or combinations thereof.
  • Polymeric coatings suitable for this invention may include, but are not limited to, a thermoplastic coating having a thermoplastic melt temperature wherein the polymeric coating is applied to the particle surface coincident with or followed by a temperature of the treated superabsorbent polymer particle at about the thermoplastic melt temperature.
  • thermoplastic polymers include, but are not limited to, polyolefin, polyethylene, polyester, polyamide, polyurethane, styrene polybutadiene, linear low density polyethylene (LLDPE), ethylene acrylic acid copolymer (EAA), ethylene alkyl methacrylate copolymer (EMA), polypropylene (PP), maleated polypropylene, ethylene vinyl acetate copolymer (EVA), polyester, polyamide, and blends of all families of polyolefins, such as blends of PP, EVA, EMA, EEA, EBA, HDPE, MDPE, LDPE, LLDPE, and/or VLDPE, may also be advantageously employed.
  • the term polyolefin as used herein is defined above.
  • a thermoplastic polymer may be functionalized to have additional benefits such as water solubility or dispersability.
  • Polymeric coatings of this invention may also include a cationic polymer.
  • a cationic polymer as used herein refers to a polymer or mixture of polymers comprising a functional group or groups having a potential of becoming positively charged ions upon ionization in an aqueous solution.
  • Suitable functional groups for a cationic polymer include, but are not limited to, primary, secondary, or tertiary amino groups, imino groups, imido groups, amido groups, and quaternary ammonium groups.
  • Examples of synthetic cationic polymers include, but are not limited to, the salts or partial salts of poly(vinyl amines), poly(allylamines), poly(ethylene imine), poly(amino propanol vinyl ethers), poly(acrylamidopropyl trimethyl ammonium chloride), poly(diallyldimethyl ammonium chloride).
  • Poly(vinyl amines) include, but are not limited to, LUPAMIN®9095 available from BASF Corporation, Mount Olive, N.J.
  • Examples of natural-based cationic polymers include, but are not limited to, partially deacetylated chitin, chitosan, and chitosan salts.
  • Synthetic polypeptides such as polyasparagins, polylysines, polyglutamines, and polyarginines are also suitable cationic polymers.
  • the superabsorbent polymer compositions according to the invention may include from 0 to about 5 wt %, or from 0.05 to about 2.0 wt %, of a multivalent metal salt, based on the dry superabsorbent polymer composition.
  • the multivalent metal salt may be applied to the surface of the superabsorbent polymer composition.
  • the multivalent metal salt is preferably water soluble.
  • preferred metal cations include the cations of Al, Fe, Zr, Mg and Zn.
  • the metal cation has a valence of at least +3, with Al being most preferred.
  • Examples of preferred anions in the multivalent metal salt include halides, chlorohydrates, sulfates, lactates, nitrates and acetates, with chlorides, sulfates, chlorohydrates and acetates being preferred, chlorohydrates and sulfates being more preferred and sulfates being the most preferred.
  • Aluminium sulfate is the most preferred multivalent metal salt and is readily commercially available.
  • the multivalent metal salt may be aluminum sulfate such as hydrated aluminum sulfate, such as aluminum sulfate having from 12 to 14 waters of hydration.
  • the multivalent metal salt may be aluminum lactate. Mixtures of multivalent metal salts can be employed.
  • the superabsorbent polymer compositions according to the invention may include from about 0.01% to about 2% by weight or from about 0.01% to about 1% by weight based on the dry superabsorbent polymer composition of a water-insoluble inorganic metal compound.
  • the water-insoluble inorganic metal compound may be applied to the surface of the superabsorbent polymer composition.
  • the water-insoluble inorganic metal compound may include, but are not limited to, a cation selected from aluminum, titanium, calcium, or iron and an anion selected from phosphate, borate, or chromate. Examples of water-insoluble inorganic metal compounds include aluminum phosphate and an insoluble metal borate.
  • the insoluble metal borate is selected from titanium borate, aluminum borate, iron borate, magnesium borate, manganese borate, or calcium borate.
  • the chemical formula TiBO will be used herein to designate titanium borate and analogous compounds such as titanium (III) borate TiBO 3 .
  • the chemical formulation also designates the case when titanium (III) borate TiBO 3 is treated with hydrogen peroxide to obtain titanium (IV) borate.
  • the inorganic metal compound may have a mass median particle size of less than about 2 ⁇ m, and may have a mass median particle size of less than about 1 ⁇ m.
  • the inorganic metal compound can be applied in the dry physical form to the surface of the superabsorbent polymer particles.
  • the superabsorbent polymer particles can be intimately mixed with the finely divided inorganic metal compound.
  • the finely divided inorganic metal compound is usually added at about room temperature to the superabsorbent polymer particles and mixed in until a homogeneous mixture is present.
  • mixing is effected in suitable mixers known in the art, such as fluidized bed mixers, paddle mixers, rotary drum mixers, or twin-worm mixers.
  • the mixing of the superabsorbent polymer particles with the finely divided water-insoluble inorganic metal compound may take place before or after any surface crosslinking, for example during the application of the surface crosslinking agent.
  • a suspension of a finely divided water-insoluble inorganic metal compounds can be prepared and applied to a particulate water absorbent polymer.
  • the suspension is applied, for example, by spraying.
  • Useful dispersion media for preparing the suspension include water, organic solvents such as alcohols, for example methanol, ethanol, isopropanol, ketones, for example acetone, methyl ethyl ketone, or mixtures of water with the aforementioned organic solvents.
  • Other useful dispersion media include dispersion aids, surfactants, protective colloidals, viscosity modifiers, and other auxiliaries to assist in the preparation of the suspension.
  • the suspension can be applied in conventional reaction mixers or mixing and drying systems as described above at a temperature in the range from room temperature to less than the boiling point of the dispersion medium, preferably at about room temperature. It is appropriate to combine the application of the suspension with a surface crosslinking step by dispersing the finely divided water-insoluble metal salt in the solution of the surface crosslinking agent. Alternatively, the suspension can also be applied before or after the surface crosslinking step. The application of the slurry may be followed by a drying step.
  • the superabsorbent polymer compositions according to the invention can include from 0% to about 5%, or in the alternative from about 0.01% to about 3%, by weight of the dry superabsorbent polymer composition of silica.
  • silica include fumed silica, precipitated silica, silicon dioxide, silicic acid, and silicates. In some particular aspects, microscopic noncrystalline silicon dioxide is desirable. Products include SIPERNAT®22S and AEROSIL®200 available from Degussa Corporation, Parsippany, N.J.
  • the particle diameter of the inorganic powder can be 1,000 ⁇ m or smaller, such as 100 ⁇ m or smaller.
  • the superabsorbent polymer compositions may also include from 0% to about 30% by weight of the dry superabsorbent polymer composition, such as from about 0.1% to about 5% by weight, of water-soluble polymers based by weight of the dry superabsorbent polymer composition, of partly or completely hydrolyzed polyvinyl acetate, polyvinylpyrrolidone, starch or starch derivatives, polyglycols, polyethylene oxides, polypropylene oxides, or polyacrylic acids.
  • additional surface additives may optionally be employed with the superabsorbent polymer particles, such as odor-binding substances, such as cyclodextrins, zeolites, inorganic or organic salts, and similar materials; anti-caking additives, flow modification agents, surfactants, viscosity modifiers, and the like.
  • surface additives may be employed that perform several roles during surface modifications. For example, a single additive may be a surfactant, viscosity modifier, and may react to crosslink polymer chains.
  • the superabsorbent polymer compositions of the present invention may, after a heat treatment step, be treated with water so that the superabsorbent polymer composition has a water content of up to about 10% by weight of the superabsorbent polymer composition.
  • This water may be added with one or more of the surface additives from above added to the superabsorbent polymer.
  • the superabsorbent polymer compositions according to the invention are desirably prepared by two methods.
  • the composition can be prepared continuously or discontinuously in a large-scale industrial manner, the after-crosslinking according to the invention being carried out accordingly.
  • the partially neutralized monomer such as acrylic acid
  • the gel is converted into a gel by free-radical polymerization in aqueous solution in the presence of crosslinking agents and any further components, and the gel is comminuted, dried, ground, and sieved off to the desired particle size.
  • This polymerization can be carried out continuously or discontinuously.
  • the size of the high-capacity superabsorbent polymer composition particles is dependent on manufacturing processes including milling and sieving. It is well known to those skilled in the art that particle size distribution of the superabsorbent polymer particles resembles a normal distribution or a bell shaped curve. It is also known that for various reasons, the normal distribution of the particle size distribution may be skewed in either direction.
  • the superabsorbent polymer particles of the present invention generally include particle sizes ranging from about 50 to about 1000 ⁇ m, or from about 150 to about 850 ⁇ m.
  • the present invention may include at least about 40 wt % of the particles having a particle size from about 300 ⁇ m to about 600 ⁇ m, at least about 50 wt % of the particles having a particle size from about 300 ⁇ m to about 600 ⁇ m, or at least about 60 wt % of the particles having a particle size from about 300 ⁇ m to about 600 ⁇ m as measured by screening through a U.S. standard 30 mesh screen and retained on a U.S. standard 50 mesh screen.
  • the size distribution of the superabsorbent polymer particles of the present invention may include less than about 30% by weight of particles having a size greater than about 600 microns, and less than about 30% by weight of particles having a size of less than about 300 microns as measured using for example a RO-TAP® Mechanical Sieve Shaker Model B available from W. S. Tyler, Inc., Mentor Ohio.
  • the form of particles may be used by way of example of the physical form of superabsorbent polymer composition, the invention is not limited to this form and is applicable to other forms such as fibers, foams, films, beads, rods, and the like, as discussed above.
  • the superabsorbent polymer composition exists as particles or in granule form, it is desirable that these particles have a size of from about 150 ⁇ m to about 850 ⁇ m based on the sieving process that is well known in the superabsorbent industry.
  • inverse suspension and emulsion polymerization can also be used for preparation of the products according to the invention.
  • an aqueous, partly neutralized solution of monomer such as acrylic acid
  • a hydrophobic, organic solvent with the aid of protective colloids and/or emulsifiers, and the polymerization is started by free radical initiators.
  • the internal crosslinking agents may be either dissolved in the monomer solution and are metered in together with this, or are added separately and optionally during the polymerization.
  • the addition of a water-soluble polymer as the graft base optionally takes place via the monomer solution or by direct introduction into the organic solvent.
  • Internal crosslinking can be carried out by polymerizing-in a polyfunctional crosslinking agent dissolved in the monomer solution and/or by reaction of suitable crosslinking agents with functional groups of the polymer during the polymerization steps.
  • a superabsorbent pre-product as used herein is produced by repeating all of the steps for making the superabsorbent, up to and including drying the material, and coarse grinding in a crusher, and removing particles greater than about 850 ⁇ m and smaller than about 150 ⁇ m.
  • the superabsorbent polymer composition of the present invention may exhibit certain characteristics, or properties, as measured by Free Swell Gel Bed Permeability (FSGBP), certain whiteness characteristics as measured by Whiteness Index Test, and residual monomer of the superabsorbent polymer composition of the present invention is set forth in the Residual Monoethylenically Unsaturated Monomer Test.
  • the Free Swell Gel Bed Permeability Test is a measurement of the permeability of a swollen bed of superabsorbent material in Darcy (e.g., separate from the absorbent structure) under a confining pressure after what is commonly referred to as “free swell” conditions.
  • the superabsorbent polymer compositions of the present invention may have a Free Swell Gel Bed Permeability of about 6 Darcy or more; or about 10 Darcy or more; or about 20 Darcy or more; or from about 6 Darcy to about 200 Darcy; or from about 10 Darcy to about 180 Darcy, or from about 20 to about 160 Darcy.
  • the superabsorbent polymer composition may have a whiteness index of at least about 7.5 after aging of about 42 days, or a whiteness index of at least about 7.5 after aging of about 49 days, or a whiteness index of at least about 7.5 after aging of about 62 days as measured by the Whiteness Index Test.
  • the superabsorbent polymer composition may have a residual monomer of less than about 200 ppm, or have a monomer of less than about 100 ppm as measured by the Residual Monoethylenically Unsaturated Monomer Test.
  • the superabsorbent polymer compositions according to the present invention can be employed in many products including sanitary towels, diapers, or wound coverings, and they have the property that they rapidly absorb large amounts of menstrual blood, urine, or other body fluids. Since the agents according to the invention retain the absorbed liquids even under pressure and are also capable of distributing further liquid within the construction in the swollen state, they are more desirably employed in higher concentrations, with respect to the hydrophilic fiber material, such as fluff, when compared to conventional current superabsorbent compositions. They are also suitable for use as a homogeneous superabsorber layer without fluff content within the diaper construction, as a result of which particularly thin articles are possible. The polymers are furthermore suitable for use in hygiene articles (incontinence products) for adults.
  • the superabsorbent polymer compositions according to the invention may also be employed in absorbent articles that are suitable for further uses.
  • the superabsorbent polymer compositions of this invention can be used in absorbent compositions for absorbents for water or aqueous liquids, desirably in constructions for absorption of body fluids, in foamed and non-foamed sheet-like structures, in packaging materials, in constructions for plant growing, as soil improvement agents, or as active compound carriers.
  • they are processed into a web by mixing with paper or fluff or synthetic fibers or by distributing the superabsorbent polymer composition particles between substrates of paper, fluff, or non-woven textiles, or by processing into carrier materials.
  • They are further suited for use in absorbent compositions such as wound dressings, packaging, agricultural absorbents, food trays and pads, and the like.
  • the superabsorbent polymer compositions according to the invention show a significant improvement in permeability, i.e. an improvement in the transportation of liquid in the swollen state, while maintaining high absorption and retention capacity, as compared to known superabsorbent polymer compositions.
  • the residual monoethylenically unsaturated monomer analysis is carried out using solid film obtained from the polymer solution or superabsorbent composition.
  • the monoethylenically unsaturated monomer is acrylic acid.
  • HPLC High performance liquid chromatography
  • SPD-10Avp Shimadzu UV detector available from Shimadzu Scientific Instruments, having a place of business in Columbia, Md., U.S.A is used to determine the residual acrylic acid monomer content.
  • the peak area of resulting elutes calculated from the chromatogram is then used to calculate the amount of residual acrylic acid monomer in the polymer. Initially, a calibration curve was generated by plotting the response area of pure acrylic acid elutes against its known amount (ppm). A linear curve with a correlation coefficient of greater than 0.996 was obtained.
  • the CIE L*, a*, b* color (D65/10) and opacity (Y) were determined using a ColorFlex® Spectrocolorimeter (commercially available from Hunter Associates Laboratory, Reston, Va.) with 5 mm ring and white ceramic and black glass disks.
  • “L*” represents lightness (100-0), “a*” redness (+) or greenness ( ⁇ ), and “b*” yellowness (+) or blueness ( ⁇ ) of the sample on the CIE L*, a*, b* scale. This scale is based on the principles described in ASTM E 308 Standard Practice for Computing the Colors of Objects by Using the CIE System.
  • the Free-Swell Gel Bed Permeability Test also referred to as the Gel Bed Permeability (GBP) Under 0 psi Swell Pressure Test, determines the permeability of a swollen bed of gel particles (e.g., such as the surface treated absorbent material or the superabsorbent material prior to being surface treated), under what is commonly referred to as “free swell” conditions.
  • the term “free swell” means that the gel particles are allowed to swell without a restraining load upon absorbing test solution as will be described.
  • a suitable apparatus for conducting the Gel Bed Permeability Test is shown in FIGS. 1 , 2 and 3 and indicated generally as 500 .
  • the test apparatus assembly 528 comprises a sample container, generally indicated as 530 , and a plunger, generally indicated as 538 .
  • the plunger comprises a shaft 538 having a cylinder hole bored down the longitudinal axis and a head 550 positioned at the bottom of the shaft.
  • the shaft hole 562 has a diameter of about 16 mm.
  • the plunger head is attached to the shaft, such as by adhesion. Twelve holes 445 are bored into the radial axis of the shaft, three positioned at every 90 degrees having diameters of about 6.4 mm.
  • the shaft 538 is machined from a LEXAN rod or equivalent material and has an outer diameter of about 2.2 cm and an inner diameter of about 16 mm.
  • the plunger head 550 has a concentric inner ring of seven holes 560 and an outer ring of 14 holes 554 , all holes having a diameter of about 8.8 millimeters as well as a hole of about 16 mm aligned with the shaft.
  • the plunger head 550 is machined from a LEXAN rod or equivalent material and has a height of approximately 16 mm and a diameter sized such that it fits within the cylinder 534 with minimum wall clearance but still slides freely.
  • the total length of the plunger head 550 and shaft 538 is about 8.25 cm, but can be machined at the top of the shaft to obtain the desired mass of the plunger 536 .
  • the plunger 536 comprises a 100 mesh stainless steel cloth screen 564 that is biaxially stretched to tautness and attached to the lower end of the plunger 536 .
  • the screen is attached to the plunger head 550 using an appropriate solvent that causes the screen to be securely adhered to the plunger head 550 . Care must be taken to avoid excess solvent migrating into the open portions of the screen and reducing the open area for liquid flow.
  • Acrylic solvent Weld-on 4 from IPS Corporation (having a place of business in Gardena, Calif., USA) is a suitable solvent.
  • the sample container 530 comprises a cylinder 534 and a 400 mesh stainless steel cloth screen 566 that is biaxially stretched to tautness and attached to the lower end of the cylinder 534 .
  • the screen is attached to the cylinder using an appropriate solvent that causes the screen to be securely adhered to the cylinder. Care must be taken to avoid excess solvent migrating into the open portions of the screen and reducing the open area for liquid flow.
  • Acrylic solvent Weld-on 4 from IPS Corporation (having a place of business in Gardena, Calif., USA) is a suitable solvent.
  • a gel particle sample, indicated as 568 in FIG. 2 is supported on the screen 566 within the cylinder 534 during testing.
  • the cylinder 534 may be bored from a transparent LEXAN rod or equivalent material, or it may be cut from a LEXAN tubing or equivalent material, and has an inner diameter of about 6 cm (e.g., a cross-sectional area of about 28.27 cm 2 ), a wall thickness of about 0.5 cm and a height of approximately 7.95 cm.
  • a step is machined into the outer diameter of the cylinder 534 such that a region 534 a with an outer diameter of 66 mm exists for the bottom 31 mm of the cylinder 534 .
  • An o-ring 540 which fits the diameter of region 534 a may be placed at the top of the step.
  • the annular weight 548 has a counter-bored hole about 2.2 cm in diameter and 1.3 cm deep so that it slips freely onto the shaft 538 .
  • the annular weight also has a thru-bore 548 a of about 16 mm.
  • the annular weight 548 can be made from stainless steel or from other suitable materials resistant to corrosion in the presence of the test solution, which is 0.9 weight percent sodium chloride solution in distilled water.
  • the combined weight of the plunger 536 and annular weight 548 equals approximately 596 grams (g), which corresponds to a pressure applied to the sample 568 of about 0.3 pounds per square inch (psi), or about 20.7 dynes/cm 2 (2.07 kPa), over a sample area of about 28.27 cm 2 .
  • the sample container 530 When the test solution flows through the test apparatus during testing as described below, the sample container 530 generally rests on a weir 600 .
  • the purpose of the weir is to divert liquid that overflows the top of the sample container 530 and diverts the overflow liquid to a separate collection device 601 .
  • the weir can be positioned above a scale 602 with a beaker 603 resting on it to collect saline solution passing through the swollen sample 568 .
  • the plunger 536 To conduct the Gel Bed Permeability Test under “free swell” conditions, the plunger 536 , with the weight 548 seated thereon, is placed in an empty sample container 530 and the height from the top of the weight 548 to the bottom of the sample container 530 is measured using a suitable gauge accurate to 0.01 mm.
  • the force the thickness gauge applies during measurement should be as low as possible, preferably less than about 0.74 Newtons. It is important to measure the height of each empty sample container 530 , plunger 536 , and weight 548 combination and to keep track of which plunger 536 and weight 548 is used when using multiple test apparatus.
  • the same plunger 536 and weight 548 should be used for measurement when the sample 568 is later swollen following saturation. It is also desirable that the base that the sample cup 530 is resting on is level, and the top surface of the weight 548 is parallel to the bottom surface of the sample cup 530 .
  • the sample to be tested is prepared from superabsorbent polymer composition particles which are prescreened through a U.S. standard 30 mesh screen and retained on a U.S. standard 50 mesh screen.
  • the test sample comprises particles sized in the range of about 300 to about 600 microns.
  • the superabsorbent polymer particles can be pre-screened with, for example, a RO-TAP Mechanical Sieve Shaker Model B available from W. S. Tyler, Inc., Mentor Ohio. Sieving is conducted for 10 minutes. Approximately 2.0 grams of the sample is placed in the sample container 530 and spread out evenly on the bottom of the sample container.
  • the container with 2.0 grams of sample in it, without the plunger 536 and weight 548 therein, is then submerged in the 0.9% saline solution for a time period of about 60 minutes to saturate the sample and allow the sample to swell free of any restraining load.
  • the sample cup 530 is set on a mesh located in the liquid reservoir so that the sample cup 530 is raised slightly above the bottom of the liquid reservoir. The mesh does not inhibit the flow of saline solution into the sample cup 530 .
  • a suitable mesh can be obtained as part number 7308 from Eagle Supply and Plastic, having a place of business in Appleton, Wis., U.S.A.
  • Saline does not fully cover the superabsorbent polymer composition particles, as would be evidenced by a perfectly flat saline surface in the test cell. Also, saline depth is not allowed to fall so low that the surface within the cell is defined solely by swollen superabsorbent, rather than saline.
  • the plunger 536 and weight 548 assembly is placed on the saturated sample 568 in the sample container 530 and then the sample container 530 , plunger 536 , weight 548 , and sample 568 are removed from the solution. After removal and before being measured, the sample container 530 , plunger 536 , weight 548 , and sample 568 are to remain at rest for about 30 seconds on a suitable flat, large grid non-deformable plate of uniform thickness.
  • the thickness of the saturated sample 568 is determined by again measuring the height from the top of the weight 548 to the bottom of the sample container 530 , using the same thickness gauge used previously provided that the zero point is unchanged from the initial height measurement.
  • the sample container 530 , plunger 536 , weight 548 , and sample 568 may be placed on a flat, large grid non-deformable plate of uniform thickness that will prevent liquid in the sample container from being released onto a flat surface due to surface tension.
  • the plate has an overall dimension of 7.6 cm by 7.6 cm, and each grid has a cell size dimension of 1.59 cm long by 1.59 cm wide by 1.12 cm deep.
  • a suitable flat, large grid non-deformable plate material is a parabolic diffuser panel, catalogue number 1624K27, available from McMaster Carr Supply Company, having a place of business in Chicago, Ill., U.S.A., which can then be cut to the proper dimensions.
  • This flat, large mesh non-deformable plate must also be present when measuring the height of the initial empty assembly.
  • the height measurement should be made as soon as practicable after the thickness gauge is engaged.
  • the height measurement obtained from measuring the empty sample container 530 , plunger 536 , and weight 548 is subtracted from the height measurement obtained after saturating the sample 568 .
  • the resulting value is the thickness, or height “H” of the swollen sample.
  • the permeability measurement is initiated by delivering a flow of the 0.9% saline solution into the sample container 530 with the saturated sample 568 , plunger 536 , and weight 548 inside.
  • the flow rate of test solution into the container is adjusted to cause saline solution to overflow the top of the cylinder 534 thereby resulting in a consistent head pressure equal to the height of the sample container 530 .
  • the test solution may be added by any suitable means that is sufficient to ensure a small, but consistent amount of overflow from the top of the cylinder, such as with a metering pump 604 .
  • the overflow liquid is diverted into a separate collection device 601 .
  • the quantity of solution passing through the sample 568 versus time is measured gravimetrically using the scale 602 and beaker 603 . Data points from the scale 602 are collected every second for at least sixty seconds once the overflow has begun. Data collection may be taken manually or with data collection software.
  • the flow rate, Q, through the swollen sample 568 is determined in units of grams/second (g/s) by a linear least-square fit of fluid passing through the sample 568 (in grams) versus time (in seconds).
  • the dried material was coarse-ground in a Prodeva Model 315-S crusher, milled in an MPI 666-F three-stage roller mill and sieved with an Minox MTS 600DS3V to remove particles greater than 850 ⁇ m and smaller than 150 ⁇ m.
  • Preproduct A was coated with 1 wt % ethylene carbonate and 4 wt % water using a 20 wt % aqueous solution and the amount of Antioxidant and Chelating Agent set forth in Table 1.
  • the coated Preproduct A was then heated in a convection oven at 190° C. for 45 minutes.
  • the surface crosslinked particulate material was then post treated with 1000 ppm polyethylene glycol 8000 (polyethylene glycol with average molecular weight of 8000) and 5% water.
  • Preproduct B was coated with 1 wt % ethylene carbonate and 4 wt % water using a 20 wt % aqueous solution. The coated Preproduct B was then heated in a convection oven at 190° C. for 30 minutes. The surface crosslinked particulate material was then post treated with 1000 ppm polyethylene glycol 8000 (polyethylene glycol with average molecular weight of 8000) and 5% water.
  • Each sample treated with NaHSO 3 was then surface cross-linked by spraying with 1 wt % ethylene carbonate and 4 wt % water using a 20 wt % aqueous solution followed by heating in a convection oven at 190° C. for 30 minutes.
  • the surface cross-linked particulate material was then post treated with 1000 ppm polyethylene glycol 8000 (polyethylene glycol with average molecular weight of 8000) and 5% water.

Landscapes

  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Veterinary Medicine (AREA)
  • Hematology (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Dispersion Chemistry (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)
  • Absorbent Articles And Supports Therefor (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Treatments Of Macromolecular Shaped Articles (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Polymerisation Methods In General (AREA)
US11/778,372 2007-07-16 2007-07-16 Superabsorbent polymer compositions having color stability Expired - Fee Related US7816426B2 (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US11/778,372 US7816426B2 (en) 2007-07-16 2007-07-16 Superabsorbent polymer compositions having color stability
KR1020107001034A KR101474229B1 (ko) 2007-07-16 2007-12-28 색상 안정성을 갖는 고흡수성 중합체 조성물
PCT/US2007/089047 WO2009011717A1 (en) 2007-07-16 2007-12-28 Superabsorbent polymer compositions having color stability
CN2007800537912A CN101802029B (zh) 2007-07-16 2007-12-28 具有颜色稳定性的超吸收性聚合物组合物
JP2010516971A JP5164229B2 (ja) 2007-07-16 2007-12-28 色安定性を有する超吸収性ポリマー組成物
EP07866086.7A EP2167552B1 (en) 2007-07-16 2007-12-28 Superabsorbent polymer compositions having color stability
TW097122668A TWI406875B (zh) 2007-07-16 2008-06-18 具色安定性之超吸收聚合物組成物
US12/884,713 US8063118B2 (en) 2007-07-16 2010-09-17 Superabsorbent polymer compositions having color stability
US13/296,861 US8236876B2 (en) 2007-07-16 2011-11-15 Superabsorbent polymer compositions having color stability

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11/778,372 US7816426B2 (en) 2007-07-16 2007-07-16 Superabsorbent polymer compositions having color stability

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US12/884,713 Continuation US8063118B2 (en) 2007-07-16 2010-09-17 Superabsorbent polymer compositions having color stability

Publications (2)

Publication Number Publication Date
US20090023848A1 US20090023848A1 (en) 2009-01-22
US7816426B2 true US7816426B2 (en) 2010-10-19

Family

ID=39643790

Family Applications (3)

Application Number Title Priority Date Filing Date
US11/778,372 Expired - Fee Related US7816426B2 (en) 2007-07-16 2007-07-16 Superabsorbent polymer compositions having color stability
US12/884,713 Expired - Fee Related US8063118B2 (en) 2007-07-16 2010-09-17 Superabsorbent polymer compositions having color stability
US13/296,861 Active US8236876B2 (en) 2007-07-16 2011-11-15 Superabsorbent polymer compositions having color stability

Family Applications After (2)

Application Number Title Priority Date Filing Date
US12/884,713 Expired - Fee Related US8063118B2 (en) 2007-07-16 2010-09-17 Superabsorbent polymer compositions having color stability
US13/296,861 Active US8236876B2 (en) 2007-07-16 2011-11-15 Superabsorbent polymer compositions having color stability

Country Status (7)

Country Link
US (3) US7816426B2 (enExample)
EP (1) EP2167552B1 (enExample)
JP (1) JP5164229B2 (enExample)
KR (1) KR101474229B1 (enExample)
CN (1) CN101802029B (enExample)
TW (1) TWI406875B (enExample)
WO (1) WO2009011717A1 (enExample)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080234420A1 (en) * 2007-03-23 2008-09-25 Smith Scott J High permeability superabsorbent polymer compositions
US20100057027A1 (en) * 2006-02-28 2010-03-04 Franck Furno Biodegradable superabsorbent polymer composition with good absorption and retention properties
US20100100066A1 (en) * 2008-10-20 2010-04-22 Azad Michael M Superabsorbent polymer containing clay, particulate, and method of making same
US20100130355A1 (en) * 2008-11-25 2010-05-27 Gonglu Tian Water-absorbing polysaccharide and method for producing the same
US20100261604A1 (en) * 2007-12-19 2010-10-14 Norbert Herfert Process for Producing Surface Crosslinked Superabsorbents
US20110121231A1 (en) * 2008-10-22 2011-05-26 Evonik Stockhausen Inc. Recycling superabsorbent polymer fines
US20110224381A1 (en) * 2010-03-15 2011-09-15 Basf Se Process for Producing Water Absorbing Polymer Particles with Improved Color stability
US8734948B2 (en) 2008-01-30 2014-05-27 Evonik Stockhausen, Llc Superabsorbent polymer compositions having a triggering composition
US8802786B2 (en) 2011-04-21 2014-08-12 Evonik Corporation Particulate superabsorbent polymer composition having improved performance properties
US8859758B2 (en) 2004-06-21 2014-10-14 Evonik Degussa Gmbh Water-absorbing polymer
US8871880B2 (en) 2012-03-22 2014-10-28 Evonik Corporation Superabsorbent copolymer
US9302248B2 (en) 2013-04-10 2016-04-05 Evonik Corporation Particulate superabsorbent polymer composition having improved stability
US9375507B2 (en) 2013-04-10 2016-06-28 Evonik Corporation Particulate superabsorbent polymer composition having improved stability
US9534095B2 (en) 2006-04-21 2017-01-03 Evonik Degussa Gmbh Water-absorbing polymer structure having improved permeability and absorption under pressure
US20170297002A1 (en) * 2014-12-10 2017-10-19 Lg Chem, Ltd. Method of preparing superabsorbent polymer
US10189008B2 (en) 2012-10-24 2019-01-29 Evonik Degussa Gmbh Odor and color stable water-absorbing composition
US10287379B2 (en) 2014-03-05 2019-05-14 Evonik Degussa Gmbh Superabsorbent polymers with improved odor control capacity and process for the production thereof
US11680184B2 (en) 2014-07-25 2023-06-20 Evonik Superabsorber Gmbh Anti-stick processing aids and use thereof in the production of water-absorbing particles

Families Citing this family (75)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1808152B1 (en) 2003-02-12 2012-08-29 The Procter and Gamble Company Absorbent Core for an Absorbent Article
EP1911425B1 (en) 2003-02-12 2014-01-15 The Procter and Gamble Company Absorbent core for an absorbent article
US7169843B2 (en) * 2003-04-25 2007-01-30 Stockhausen, Inc. Superabsorbent polymer with high permeability
DE10334286B4 (de) 2003-07-25 2006-01-05 Stockhausen Gmbh Pulverförmige,wasserabsorbierende Polymere mit mittels thermoplastischen Klebstoffen gebundenen Feinteilchen, Verfahren zu deren Herstellung sowie diese beinhaltende chemische Produkte und Verbunde
US7173086B2 (en) 2003-10-31 2007-02-06 Stockhausen, Inc. Superabsorbent polymer with high permeability
DE112008000010B4 (de) 2007-06-18 2013-08-22 The Procter & Gamble Company Einwegabsorptionsartikel mit im wesentlichen kontinuierlich verteilten, teilchenförmigem polymerem Absorptionsmaterial und Verfahren zu dessen Herstellung
GB2454301B (en) 2007-06-18 2012-03-28 Procter & Gamble Disposable absorbent article with sealed absorbent core with substantially continuously distributed absorbent particulate polymer material
US7816426B2 (en) * 2007-07-16 2010-10-19 Evonik Stockhausen, Llc Superabsorbent polymer compositions having color stability
DE102007045724B4 (de) 2007-09-24 2012-01-26 Evonik Stockhausen Gmbh Superabsorbierende Zusammensetzung mit Tanninen zur Geruchskontrolle, Verfahren zu deren Herstellung und Verwendung
DE102007053619A1 (de) * 2007-11-08 2009-05-20 Evonik Stockhausen Gmbh Wasserabsorbierende Polymergebilde mit verbesserter Farbstabilität
WO2009134780A1 (en) 2008-04-29 2009-11-05 The Procter & Gamble Company Process for making an absorbent core with strain resistant core cover
EP2307486B2 (de) 2008-07-31 2019-10-23 Basf Se Farbstabiler superabsorber
US8477247B2 (en) * 2008-09-30 2013-07-02 Intel Corporation Joint enhancement of lightness, color and contrast of images and video
US8608096B2 (en) * 2009-02-18 2013-12-17 Basf Se Method for the production of water-absorbing polymer particles
KR101648072B1 (ko) * 2009-07-03 2016-08-12 삼성전자 주식회사 유기 반도체 고분자 및 이를 포함하는 트랜지스터
EP2484702B2 (en) 2009-09-30 2021-11-10 Nippon Shokubai Co., Ltd. Polyacrylic acid salt-based water absorbent resin and method for producing same
WO2011042404A1 (de) * 2009-10-09 2011-04-14 Basf Se Verwendung von heizdampfkondensat zur herstellung wasserabsorbierender polymerpartikel
EP2329803B1 (en) 2009-12-02 2019-06-19 The Procter & Gamble Company Apparatus and method for transferring particulate material
EP2371869A1 (en) 2010-03-30 2011-10-05 Evonik Stockhausen GmbH A process for the production of a superabsorbent polymer
WO2011131526A1 (de) * 2010-04-19 2011-10-27 Basf Se Verfahren zur herstellung wasserabsorbierender polymerpartikel
US8791230B2 (en) 2010-06-08 2014-07-29 Nippon Shokubai Co., Ltd. Method for producing particulate water absorbent resin
PL3338751T3 (pl) 2011-06-10 2020-04-30 The Procter & Gamble Company Struktura chłonna do wyrobów chłonnych
ES2484695T5 (es) 2011-06-10 2018-02-13 The Procter & Gamble Company Pañal desechable que tiene una unión reducida entre el núcleo absorbente y la lámina de respaldo
EP2532329B1 (en) 2011-06-10 2018-09-19 The Procter and Gamble Company Method and apparatus for making absorbent structures with absorbent material
JP5940655B2 (ja) 2011-06-10 2016-06-29 ザ プロクター アンド ギャンブル カンパニー 使い捨て吸収性物品のための吸収性コア
MX2013014588A (es) 2011-06-10 2014-01-24 Procter & Gamble Estructura absorbente para articulos absorbentes.
EP2532328B1 (en) 2011-06-10 2014-02-26 The Procter and Gamble Company Method and apparatus for making absorbent structures with absorbent material
WO2012170781A1 (en) 2011-06-10 2012-12-13 The Procter & Gamble Company Disposable diapers
DE102011086522A1 (de) * 2011-11-17 2013-05-23 Evonik Degussa Gmbh Superabsorbierende Polymere für hochgefüllte oder faserfreie Hygieneartikel
KR20140142740A (ko) * 2012-03-30 2014-12-12 바스프 에스이 색 안정적 초흡수체
US10111002B1 (en) * 2012-08-03 2018-10-23 Amazon Technologies, Inc. Dynamic audio optimization
KR102226473B1 (ko) * 2012-08-27 2021-03-12 가부시키가이샤 닛폰 쇼쿠바이 입자상 흡수제 및 그의 제조 방법
GB2510665C (en) 2012-11-13 2017-01-25 Procter & Gamble Absorbent articles with channels and signals
EP2740452B1 (en) 2012-12-10 2021-11-10 The Procter & Gamble Company Absorbent article with high absorbent material content
US9216116B2 (en) 2012-12-10 2015-12-22 The Procter & Gamble Company Absorbent articles with channels
EP2740450A1 (en) 2012-12-10 2014-06-11 The Procter & Gamble Company Absorbent core with high superabsorbent material content
US9216118B2 (en) 2012-12-10 2015-12-22 The Procter & Gamble Company Absorbent articles with channels and/or pockets
US10639215B2 (en) 2012-12-10 2020-05-05 The Procter & Gamble Company Absorbent articles with channels and/or pockets
PL2740449T3 (pl) 2012-12-10 2019-07-31 The Procter & Gamble Company Artykuł chłonny o wysokiej zawartości materiału chłonnego
JP5952431B2 (ja) 2013-01-29 2016-07-13 株式会社日本触媒 吸水性樹脂材料及びその製造方法
US9599970B2 (en) * 2013-03-27 2017-03-21 The United States Of America As Represented By The Secretary Of The Navy Safety critical control system that includes control logic or machine readable instructions that selectively locks or enables the control system based on one or more machine implemented state machines that includes states associated with detection or matching of one or more predetermined signals on distinct conduction paths between elements of the control system and related methods
PL3254656T3 (pl) 2013-06-14 2022-01-10 The Procter & Gamble Company Wyrób chłonny i wkład chłonny tworzący kanały w stanie mokrym
US9950308B2 (en) 2013-08-01 2018-04-24 Lg Chem, Ltd. Superabsorbent polymer
KR101527585B1 (ko) * 2013-08-13 2015-06-09 주식회사 엘지화학 고흡수성 수지의 제조 방법
JP6334705B2 (ja) 2013-08-27 2018-05-30 ザ プロクター アンド ギャンブル カンパニー チャネルを有する吸収性物品
US9987176B2 (en) 2013-08-27 2018-06-05 The Procter & Gamble Company Absorbent articles with channels
JP6169800B2 (ja) 2013-09-16 2017-07-26 ザ プロクター アンド ギャンブル カンパニー チャネルと標識を持つ吸収性物品
EP2851048B1 (en) * 2013-09-19 2018-09-05 The Procter and Gamble Company Absorbent cores having material free areas
JP6151790B2 (ja) 2013-10-09 2017-06-21 株式会社日本触媒 吸水性樹脂を主成分とする粒子状吸水剤及びその製造方法
CA2931390A1 (en) * 2013-11-26 2015-06-04 Basf Se Polyurethane elastomeric composition and method of preparing the same
KR101700907B1 (ko) * 2013-12-10 2017-01-31 주식회사 엘지화학 고흡수성 수지의 제조 방법
US9937482B2 (en) * 2013-12-11 2018-04-10 Lg Chem, Ltd. Super absorbent polymer resin and method for preparing same
US9789009B2 (en) 2013-12-19 2017-10-17 The Procter & Gamble Company Absorbent articles having channel-forming areas and wetness indicator
PL2886092T3 (pl) 2013-12-19 2017-03-31 The Procter And Gamble Company Wkłady chłonne z obszarami tworzącymi kanały i zgrzewami osłony c
EP2905001B1 (en) 2014-02-11 2017-01-04 The Procter and Gamble Company Method and apparatus for making an absorbent structure comprising channels
WO2015163523A1 (en) * 2014-04-25 2015-10-29 Songwon Industrial Co., Ltd. Production of water-absorbent polymer particles employing a blowing agent and surface-crosslinking
EP2949300B1 (en) 2014-05-27 2017-08-02 The Procter and Gamble Company Absorbent core with absorbent material pattern
KR101949455B1 (ko) * 2015-01-07 2019-02-18 주식회사 엘지화학 내고화성이 향상된 고흡수성 수지 및 그 제조 방법
RU2017133027A (ru) 2015-03-16 2019-04-16 Дзе Проктер Энд Гэмбл Компани Абсорбирующие изделия повышенной прочности
US10322040B2 (en) 2015-03-16 2019-06-18 The Procter & Gamble Company Absorbent articles with improved cores
CN107592805B (zh) 2015-05-12 2021-07-06 宝洁公司 具有改善的芯与底片粘合剂的吸收制品
CN107683126A (zh) 2015-05-29 2018-02-09 宝洁公司 具有槽和润湿指示标记的吸收制品
CN109563210B (zh) * 2016-08-10 2021-10-08 巴斯夫欧洲公司 制备超吸收剂的方法
MY186384A (en) * 2016-12-13 2021-07-21 L Bruggemann Gmbh & Co Kg Mixed salts of hydroxyalkane sulfinic acid
KR102075733B1 (ko) 2016-12-13 2020-02-10 주식회사 엘지화학 고흡수성 수지 및 이의 제조 방법
KR102093352B1 (ko) 2016-12-19 2020-03-25 주식회사 엘지화학 고흡수성 수지의 제조 방법
JP6979770B2 (ja) * 2017-02-16 2021-12-15 Ｓｄｐグローバル株式会社 吸水性樹脂粒子及びその製造方法
CN110016324B (zh) * 2018-01-10 2021-08-17 中国石油化工股份有限公司 一种耐高温水基钻井液提切剂及其制备方法
EP3781108B1 (en) * 2018-04-20 2023-11-29 Basf Se Process for producing superabsorbents
KR102457232B1 (ko) * 2018-09-27 2022-10-20 주식회사 엘지화학 고흡수성 수지 시트의 제조 방법
WO2021162085A1 (ja) 2020-02-14 2021-08-19 株式会社日本触媒 吸水性樹脂およびその製造方法
CN115667335A (zh) * 2020-04-30 2023-01-31 金伯利-克拉克环球有限公司 基于多种带电单体的共聚物的超吸收聚合物
JP7601426B2 (ja) * 2021-01-14 2024-12-17 エルジー・ケム・リミテッド 高吸水性樹脂の製造方法
KR102584470B1 (ko) * 2021-05-28 2023-10-05 욱성화학주식회사 가압흡수성이 우수한 생분해성 기반의 고흡수성 수지 및 그의 제조방법
CN118414370A (zh) * 2021-12-21 2024-07-30 住友精化株式会社 包覆树脂粒子、吸水性树脂组合物及吸收体

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4863989A (en) 1986-06-04 1989-09-05 Seitetsu Kagaku Co., Ltd. Water-absorbent resin composition
EP0505163A1 (en) 1991-03-18 1992-09-23 Nalco Chemical Company Reduction of residual monomers in superabsorbent polymers
US5773542A (en) * 1995-03-23 1998-06-30 Kao Corporation Process for producing polymer particles
WO2000055245A1 (en) 1999-03-12 2000-09-21 Basf Aktiengesellschaft Color-stable superabsorbent polymer composition
US6211400B1 (en) 1997-10-02 2001-04-03 L. Bruggemann Kg Sulphinic acid derivatives, method for producing them, and their use
WO2004084962A1 (en) 2003-03-26 2004-10-07 Basf Aktiengesellschaft Color-stable superabsorbent polymer composition
WO2005054356A1 (de) 2003-12-03 2005-06-16 Basf Aktiengesellschaft Mindestens ein sterisch gehindertes einwertiges und/oder mehrwertiges phenol enthaltende superabsorber
US20060074160A1 (en) 2002-12-27 2006-04-06 Masayoshi Handa Water-absorbing resin composition
US20060229369A1 (en) * 2003-08-21 2006-10-12 Basf Aktiengesellschaft Use of 2-hydroxy-2-sulfinato acetic acid or the salts thereof as an initiator in w/o emulsions
WO2006109882A1 (en) 2005-04-12 2006-10-19 Nippon Shokubai Co., Ltd. Particulate water absorbing agent including polyacrylic acid (polyacrylate) based water absorbing resin as a principal component, method for production thereof, water-absorbent core and absorbing article in which the particulate water absorbing agent is used

Family Cites Families (58)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51125468A (en) * 1975-03-27 1976-11-01 Sanyo Chem Ind Ltd Method of preparing resins of high water absorbency
DE2706135C2 (de) 1977-02-14 1982-10-28 Chemische Fabrik Stockhausen GmbH, 4150 Krefeld Verdickungsmittel für ausgeschiedenen Darminhalt und Harn
US4131576A (en) 1977-12-15 1978-12-26 National Starch And Chemical Corporation Process for the preparation of graft copolymers of a water soluble monomer and polysaccharide employing a two-phase reaction system
US4286082A (en) * 1979-04-06 1981-08-25 Nippon Shokubai Kagaku Kogyo & Co., Ltd. Absorbent resin composition and process for producing same
JPS6025045B2 (ja) * 1980-03-19 1985-06-15 製鉄化学工業株式会社 塩水吸収能のすぐれたアクリル酸重合体の製造方法
JPS60163956A (ja) 1984-02-04 1985-08-26 Arakawa Chem Ind Co Ltd 吸水性樹脂の製法
DE3713601A1 (de) 1987-04-23 1988-11-10 Stockhausen Chem Fab Gmbh Verfahren zur herstellung eines stark wasserabsorbierenden polymerisats
DE3926169A1 (de) 1989-08-08 1991-02-14 Basf Ag Verfahren zur verbesserung der wasseraufnahmekapazitaet von vernetzten, wasserquellbaren polymeren
DE4020780C1 (enExample) 1990-06-29 1991-08-29 Chemische Fabrik Stockhausen Gmbh, 4150 Krefeld, De
DE4244548C2 (de) * 1992-12-30 1997-10-02 Stockhausen Chem Fab Gmbh Pulverförmige, unter Belastung wäßrige Flüssigkeiten sowie Blut absorbierende Polymere, Verfahren zu ihrer Herstellung und ihre Verwendung in textilen Konstruktionen für die Körperhygiene
DE4418818C2 (de) 1993-07-09 1997-08-21 Stockhausen Chem Fab Gmbh Pulverförmige, vernetzte, wäßrige Flüssigkeiten und/oder Körperflüssigkeiten absorbierende Polymere, Verfahren zu ihrer Herstellung und ihre Anwendung
IL110134A (en) * 1993-07-09 1998-07-15 Stockhausen Chem Fab Gmbh Polymers capable of absorbing aqueous liquids and body fluids their preparation and use
US5451613A (en) * 1993-09-17 1995-09-19 Nalco Chemical Company Superabsorbent polymer having improved absorption rate and absorption under pressure
DE4333056C2 (de) * 1993-09-29 1998-07-02 Stockhausen Chem Fab Gmbh Pulverförmige, wäßrige Flüssigkeiten absorbierende Polymere, Verfahren zu ihrer Herstellung und ihre Verwendung als Absorptionsmittel
DE69505398T2 (de) 1994-08-12 1999-03-11 Kao Corp., Tokio/Tokyo Verfahren zur herstellung von verbesserten superabsorbierenden polymeren
DE19529348C2 (de) * 1995-08-09 1997-11-20 Stockhausen Chem Fab Gmbh Absorptionsmittel für Wasser und wäßrige Flüssigkeiten auf Polyacrylatbasis sowie Verfahren zu ihrer Herstellung und Verwendung
IL137034A0 (en) 1998-01-07 2001-06-14 Procter & Gamble Absorbent polymer compositions having high sorption capacities under an applied pressure
JP2001282009A (ja) * 2000-03-31 2001-10-12 Ricoh Co Ltd 中間転写ベルトの製造方法及び中間転写ベルト、並びに、該中間転写ベルトを用いた画像形成装置
DE10053858A1 (de) * 2000-10-30 2002-05-08 Stockhausen Chem Fab Gmbh Absorbierendes Gebilde mit verbesserten Blockingeigenschaften
US20020115971A1 (en) 2000-12-20 2002-08-22 Holmes Lori Tassone Thin, high capacity multi-layer absorbent core
JP3987348B2 (ja) * 2001-01-26 2007-10-10 株式会社日本触媒 吸水剤の製法
JP2003052742A (ja) * 2001-08-09 2003-02-25 San-Dia Polymer Ltd 吸収剤及びこれを使用した吸収性構造体
US6906131B2 (en) * 2001-09-17 2005-06-14 Stockhausen Gmbh & Co. Kg Cellulose material with improved absorbency
JP3939988B2 (ja) * 2002-01-16 2007-07-04 住友精化株式会社 吸水性樹脂の製造方法
DE10218147B4 (de) * 2002-04-23 2005-12-22 Stockhausen Gmbh Wasserabsorbierende, die Zersetzung von Körperflüssigkeiten verzögernde Polymerteilchen, deren Herstellung und Verwendung
DE10241481B4 (de) * 2002-09-07 2006-07-06 Celanese Emulsions Gmbh Verfahren zum Herstellen von wässrigen Polymerdispersionen mit sehr niedrigen Restmonomergehalten und deren Verwendung
DE10249821A1 (de) 2002-10-25 2004-05-13 Stockhausen Gmbh & Co. Kg Absorbierende Polymergebilde mit verbesserter Rententionskapazität und Permeabilität
AU2003274077A1 (en) * 2002-10-25 2004-05-13 Stockhausen Gmbh Two-stage mixing method for producing an absorbent polymer
US7169843B2 (en) 2003-04-25 2007-01-30 Stockhausen, Inc. Superabsorbent polymer with high permeability
DE10334286B4 (de) 2003-07-25 2006-01-05 Stockhausen Gmbh Pulverförmige,wasserabsorbierende Polymere mit mittels thermoplastischen Klebstoffen gebundenen Feinteilchen, Verfahren zu deren Herstellung sowie diese beinhaltende chemische Produkte und Verbunde
US7163969B2 (en) * 2003-10-14 2007-01-16 Stockhausen, Inc. Superabsorbent polymer aqueous paste and coating
US7291674B2 (en) * 2003-10-28 2007-11-06 Stockhausen, Inc. Superabsorbent polymer
US7173086B2 (en) 2003-10-31 2007-02-06 Stockhausen, Inc. Superabsorbent polymer with high permeability
US7579402B2 (en) * 2003-11-12 2009-08-25 Evonik Stockhausen, Inc. Superabsorbent polymer having delayed free water absorption
DE102004028002A1 (de) * 2004-06-09 2006-01-05 Stockhausen Gmbh Verfahren zur Herstellung von hydrophilen Polymeren unter Verwendung eines rechnererzeugten Modells
EP1769004B1 (de) * 2004-06-21 2017-08-09 Evonik Degussa GmbH Wasserabsorbierendes polysaccharid sowie ein verfahren zu seiner herstellung
TWI522092B (zh) * 2005-02-28 2016-02-21 贏創德固賽有限責任公司 丙烯酸和基於可再生原料之吸水聚合物結構及二者之製備方法
DE102005010198A1 (de) * 2005-03-05 2006-09-07 Degussa Ag Hydrolysestabile, nachvernetzte Superabsorber
DE102005018922A1 (de) * 2005-04-22 2006-10-26 Stockhausen Gmbh Mit Polykationen oberflächenbehandeltes wasserabsorbierendes Polymergebilde
JP5222721B2 (ja) * 2005-04-22 2013-06-26 エフォニック ストックハウゼン ゲーエムベーハー 高吸収性を有する吸水性ポリマー構造体
DE102005018924A1 (de) * 2005-04-22 2006-10-26 Stockhausen Gmbh Wasserabsorbierende Polymergebilde mit verbesserten Absorptionseigenschaften
CN2819951Y (zh) 2005-06-16 2006-09-27 千宝实业股份有限公司 远红外线能量垫体
DE102005055497A1 (de) * 2005-11-18 2007-05-31 Stockhausen Gmbh Geruchsbindende superabsorbierende Zusammensetzung
US7335713B2 (en) * 2005-12-02 2008-02-26 Stockhausen, Inc. Method for preparing a flexible superabsorbent binder polymer composition
US7312286B2 (en) * 2005-12-02 2007-12-25 Stockhausen, Inc. Flexible superabsorbent binder polymer composition
US7812082B2 (en) * 2005-12-12 2010-10-12 Evonik Stockhausen, Llc Thermoplastic coated superabsorbent polymer compositions
US8829107B2 (en) * 2006-02-28 2014-09-09 Evonik Degussa Gmbh Biodegradable superabsorbent polymer composition with good absorption and retention properties
WO2007121937A2 (de) * 2006-04-21 2007-11-01 Evonik Stockhausen Gmbh Oberflächennachvernetzte superabsorber behandelt mit aluminiumlactat und optional aluminiumsulfat
DE102006019157A1 (de) * 2006-04-21 2007-10-25 Stockhausen Gmbh Herstellung von hochpermeablen, superabsorbierenden Polymergebilden
DE102006060156A1 (de) * 2006-12-18 2008-06-19 Evonik Stockhausen Gmbh Wasserabsorbierende Polymergebilde, welche unter Einsatz von Polymerdispersionen hergestellt wurden
US8236884B2 (en) * 2007-03-23 2012-08-07 Evonik Stockhausen, Llc High permeability superabsorbent polymer compositions
US7816426B2 (en) * 2007-07-16 2010-10-19 Evonik Stockhausen, Llc Superabsorbent polymer compositions having color stability
DE102007045724B4 (de) * 2007-09-24 2012-01-26 Evonik Stockhausen Gmbh Superabsorbierende Zusammensetzung mit Tanninen zur Geruchskontrolle, Verfahren zu deren Herstellung und Verwendung
DE102007053619A1 (de) 2007-11-08 2009-05-20 Evonik Stockhausen Gmbh Wasserabsorbierende Polymergebilde mit verbesserter Farbstabilität
US8318306B2 (en) * 2008-01-30 2012-11-27 Evonik Stockhausen, Llc Superabsorbent polymer compositions having a triggering composition
US8222477B2 (en) * 2008-10-20 2012-07-17 Evonik Stockhausen, Llc Superabsorbent polymer containing clay, particulate, and method of making same
US7910688B2 (en) * 2008-10-22 2011-03-22 Evonik Stockhausen Inc. Recycling superabsorbent polymer fines
US8361926B2 (en) * 2008-11-25 2013-01-29 Evonik Stockhausen, Llc Water-absorbing polysaccharide and method for producing the same

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4863989A (en) 1986-06-04 1989-09-05 Seitetsu Kagaku Co., Ltd. Water-absorbent resin composition
EP0505163A1 (en) 1991-03-18 1992-09-23 Nalco Chemical Company Reduction of residual monomers in superabsorbent polymers
US5773542A (en) * 1995-03-23 1998-06-30 Kao Corporation Process for producing polymer particles
US6211400B1 (en) 1997-10-02 2001-04-03 L. Bruggemann Kg Sulphinic acid derivatives, method for producing them, and their use
WO2000055245A1 (en) 1999-03-12 2000-09-21 Basf Aktiengesellschaft Color-stable superabsorbent polymer composition
US6359049B1 (en) 1999-03-12 2002-03-19 Basf Aktiengesellschaft Color-stable superabsorbent polymer composition
US20060074160A1 (en) 2002-12-27 2006-04-06 Masayoshi Handa Water-absorbing resin composition
WO2004084962A1 (en) 2003-03-26 2004-10-07 Basf Aktiengesellschaft Color-stable superabsorbent polymer composition
US20060229369A1 (en) * 2003-08-21 2006-10-12 Basf Aktiengesellschaft Use of 2-hydroxy-2-sulfinato acetic acid or the salts thereof as an initiator in w/o emulsions
WO2005054356A1 (de) 2003-12-03 2005-06-16 Basf Aktiengesellschaft Mindestens ein sterisch gehindertes einwertiges und/oder mehrwertiges phenol enthaltende superabsorber
WO2006109882A1 (en) 2005-04-12 2006-10-19 Nippon Shokubai Co., Ltd. Particulate water absorbing agent including polyacrylic acid (polyacrylate) based water absorbing resin as a principal component, method for production thereof, water-absorbent core and absorbing article in which the particulate water absorbing agent is used

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
International Search Report completed on Jul. 21, 2008 in PCT/US2007/089047.
Written Opinion mailed on Aug. 7, 2008 in PCT/US2007/089047.

Cited By (37)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8859758B2 (en) 2004-06-21 2014-10-14 Evonik Degussa Gmbh Water-absorbing polymer
US20100057027A1 (en) * 2006-02-28 2010-03-04 Franck Furno Biodegradable superabsorbent polymer composition with good absorption and retention properties
US8829107B2 (en) 2006-02-28 2014-09-09 Evonik Degussa Gmbh Biodegradable superabsorbent polymer composition with good absorption and retention properties
US9534095B2 (en) 2006-04-21 2017-01-03 Evonik Degussa Gmbh Water-absorbing polymer structure having improved permeability and absorption under pressure
US8236884B2 (en) * 2007-03-23 2012-08-07 Evonik Stockhausen, Llc High permeability superabsorbent polymer compositions
US20080234420A1 (en) * 2007-03-23 2008-09-25 Smith Scott J High permeability superabsorbent polymer compositions
US8822582B2 (en) * 2007-03-23 2014-09-02 Evonik Corporation High permeability superabsorbent polymer compositions
US20120277096A1 (en) * 2007-03-23 2012-11-01 Evonik Stockhausen Llc High permeability superabsorbent polymer compositions
US20140031498A1 (en) * 2007-03-23 2014-01-30 Evonik Stockhausen, Llc High permeability superabsorbent polymer compositions
US8519041B2 (en) * 2007-03-23 2013-08-27 Evonik Stockhausen, Llc High permeability superabsorbent polymer compositions
US20100261604A1 (en) * 2007-12-19 2010-10-14 Norbert Herfert Process for Producing Surface Crosslinked Superabsorbents
US8734948B2 (en) 2008-01-30 2014-05-27 Evonik Stockhausen, Llc Superabsorbent polymer compositions having a triggering composition
US20100100066A1 (en) * 2008-10-20 2010-04-22 Azad Michael M Superabsorbent polymer containing clay, particulate, and method of making same
US8222477B2 (en) 2008-10-20 2012-07-17 Evonik Stockhausen, Llc Superabsorbent polymer containing clay, particulate, and method of making same
US8962910B2 (en) 2008-10-20 2015-02-24 Evonik Corporation Superabsorbent polymer containing clay particulate, and method of making same
US8487049B2 (en) 2008-10-22 2013-07-16 Evonik Stockhausen, Llc Recycling superabsorbent polymer fines
US20110121231A1 (en) * 2008-10-22 2011-05-26 Evonik Stockhausen Inc. Recycling superabsorbent polymer fines
US8318895B1 (en) 2008-10-22 2012-11-27 Evonik Stockhausen, Llc Recycling superabsorbent polymer fines
US8309682B2 (en) 2008-10-22 2012-11-13 Evonik Stockhausen, Llc Recycling superabsorbent polymer fines
US8703645B2 (en) 2008-11-25 2014-04-22 Evonik Corporation Water-absorbing polysaccharide and method for producing the same
US20100130355A1 (en) * 2008-11-25 2010-05-27 Gonglu Tian Water-absorbing polysaccharide and method for producing the same
US8486855B2 (en) 2008-11-25 2013-07-16 Evonik Stockhausen Llc Water-absorbing polysaccharide and method for producing the same
US8361926B2 (en) 2008-11-25 2013-01-29 Evonik Stockhausen, Llc Water-absorbing polysaccharide and method for producing the same
US8703876B2 (en) * 2010-03-15 2014-04-22 Basf Se Process for producing water absorbing polymer particles with improved color stability
US20110224381A1 (en) * 2010-03-15 2011-09-15 Basf Se Process for Producing Water Absorbing Polymer Particles with Improved Color stability
US9102806B2 (en) 2011-04-21 2015-08-11 Evonik Corporation Particulate superabsorbent polymer composition having improved performance properties
US8802786B2 (en) 2011-04-21 2014-08-12 Evonik Corporation Particulate superabsorbent polymer composition having improved performance properties
US8871880B2 (en) 2012-03-22 2014-10-28 Evonik Corporation Superabsorbent copolymer
US10189008B2 (en) 2012-10-24 2019-01-29 Evonik Degussa Gmbh Odor and color stable water-absorbing composition
US9375507B2 (en) 2013-04-10 2016-06-28 Evonik Corporation Particulate superabsorbent polymer composition having improved stability
US9302248B2 (en) 2013-04-10 2016-04-05 Evonik Corporation Particulate superabsorbent polymer composition having improved stability
US10307732B2 (en) 2013-04-10 2019-06-04 Evonik Corporation Particulate superabsorbent polymer composition having improved stability and fast absorption
US10287379B2 (en) 2014-03-05 2019-05-14 Evonik Degussa Gmbh Superabsorbent polymers with improved odor control capacity and process for the production thereof
US10738141B2 (en) 2014-03-05 2020-08-11 Evonik Operations Gmbh Superabsorbent polymers with improved odor control capacity and process for the production thereof
US11680184B2 (en) 2014-07-25 2023-06-20 Evonik Superabsorber Gmbh Anti-stick processing aids and use thereof in the production of water-absorbing particles
US20170297002A1 (en) * 2014-12-10 2017-10-19 Lg Chem, Ltd. Method of preparing superabsorbent polymer
US10052611B2 (en) * 2014-12-10 2018-08-21 Lg Chem, Ltd. Method of preparing superabsorbent polymer

Also Published As

Publication number Publication date
JP2010533766A (ja) 2010-10-28
US8063118B2 (en) 2011-11-22
US20120083411A1 (en) 2012-04-05
TW200911849A (en) 2009-03-16
CN101802029A (zh) 2010-08-11
JP5164229B2 (ja) 2013-03-21
TWI406875B (zh) 2013-09-01
KR20100040858A (ko) 2010-04-21
CN101802029B (zh) 2012-10-10
EP2167552B1 (en) 2018-02-07
WO2009011717A1 (en) 2009-01-22
EP2167552A1 (en) 2010-03-31
KR101474229B1 (ko) 2014-12-18
US20110009841A1 (en) 2011-01-13
US8236876B2 (en) 2012-08-07
US20090023848A1 (en) 2009-01-22

Similar Documents

Publication Publication Date Title
US7816426B2 (en) Superabsorbent polymer compositions having color stability
US8236884B2 (en) High permeability superabsorbent polymer compositions
JP6720271B2 (ja) 安定性が改良された粒子状超吸収性ポリマー組成物
US8309682B2 (en) Recycling superabsorbent polymer fines
US9302248B2 (en) Particulate superabsorbent polymer composition having improved stability

Legal Events

Date Code Title Description
AS Assignment

Owner name: STOCKHAUSEN, INC., NORTH CAROLINA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:AHMED, IQBAL;WALDEN, MIRKO;KING, BRIAN;AND OTHERS;REEL/FRAME:019860/0618;SIGNING DATES FROM 20070813 TO 20070816

Owner name: STOCKHAUSEN, INC., NORTH CAROLINA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:AHMED, IQBAL;WALDEN, MIRKO;KING, BRIAN;AND OTHERS;SIGNING DATES FROM 20070813 TO 20070816;REEL/FRAME:019860/0618

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

AS Assignment

Owner name: EVONIK STOCKHAUSEN, INC., NORTH CAROLINA

Free format text: CHANGE OF NAME;ASSIGNOR:STOCKHAUSEN, INC.;REEL/FRAME:024922/0108

Effective date: 20071017

AS Assignment

Owner name: EVONIK STOCKHAUSEN, LLC, NORTH CAROLINA

Free format text: CHANGE OF NAME;ASSIGNOR:EVONIK STOCKHAUSEN, INC.;REEL/FRAME:024931/0838

Effective date: 20091021

CC Certificate of correction
FPAY Fee payment

Year of fee payment: 4

AS Assignment

Owner name: EVONIK DEGUSSA CORPORATION, NEW JERSEY

Free format text: MERGER;ASSIGNOR:EVONIK STOCKHAUSEN, LLC;REEL/FRAME:035062/0068

Effective date: 20121226

AS Assignment

Owner name: EVONIK CORPORATION, NEW JERSEY

Free format text: CHANGE OF NAME;ASSIGNOR:EVONIK DEGUSSA CORPORATION;REEL/FRAME:035074/0607

Effective date: 20130101

FEPP Fee payment procedure

Free format text: MAINTENANCE FEE REMINDER MAILED (ORIGINAL EVENT CODE: REM.)

LAPS Lapse for failure to pay maintenance fees

Free format text: PATENT EXPIRED FOR FAILURE TO PAY MAINTENANCE FEES (ORIGINAL EVENT CODE: EXP.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20181019